DE1551385B - Method and device for quick freezing food - Google Patents

Description

1 2

The invention relates to a new method and conveyor belt immersed in dichlorodifluoromethane a device for rapid freezing of near-will and measures are provided to the Aufrungsmittel in a freezing chamber, which drove a liquid to coolant the frozen goods in the refrigerant contains that prevent in direct contact with and the material to the conveyor belt in the form of individual loose particles present 5 hold (see. US Pat. Nos. 3,136,642 and Food stands. 2 059 970).

Nowadays, foods are technically The indirect contact freezing process is based on the direct contact freezing process or after the conduction of heat from the food to an indirect contact freezing process. In the refrigerant (usually brine or a part of the direct contact freezing process, there is liquid gas) through metal plates. There are three freezing methods with many modifications: The indirect freezer is widely used which is at about -15 ° C. However, this freezing process is slow. In the freezing under such conditions, long ice seeds can develop and the food crystals can form unevenly, the structure of the food crystals and break the cell walls, so that the food can be impaired and the product can be unsightly after thawing spoilage can occur before it enters (U.S. Patents 2,578,829 and 2,697,920).
freeze is over. (2) The Gebläseluft-Gefrierver- The invention is based on the object, a drive works with fans that circulate the air in the 20 new method for quick freezing food freezer. To make the high air speed available, at which the speed improves the heat transfer, but handling the frozen food particularly gently the freezing speed is still low. takes place, so that mechanical damage or abrasion can also prevent individual good parts from freezing together and damage drainage. (3) At the age of 25.

Dip freezing processes the food in this is done according to the process according to the invention A mixture of ice and salt or in cooling brine is achieved in that the frozen food falls freely submerged. The cooling brine can also be supplied to the refrigerant on the product and floating in it be sprayed on. Food that is moved and the refrigerant is attached to the Traces of salt are inadmissible, can freeze before the point of free fall in a turbulent state be packed. For immersion freezing finds.

of fruits and berries is used in place of refrigeration by U.S. Patents 3,104,977 and

brine freezing sugar syrup is used. 2 951 353 are already orders with refrigeration

Another direct contact freezing process known as medium bath, but only closed

consists in the fact that the food is processed with liquid 35 packs, so that an addition

Nitrogen, liquid nitrogen oxide, liquid carbon freezing of frozen food particles is not

Dioxide or non-toxic fluorine compounds with boiling point was prevented.

points below 0 ° C can be sprayed (USA

Patent 3,214,928). When using flüs- with disconnection of screw conveyors for the

With nitrogen as a refrigerant, the near 40 movement of non-frozen good particles and the

It gives a violent thermal shock so that it is floating in the coolant

burst or jump. Furthermore, a particularly gentle handling of the goods is achieved,

freezing costs with liquid nitrogen are high; usually by means of which it became possible to preserve the good in his own

one uses 1 kg of refrigerant per kilogram of near-natural form to freeze without doing anything

funds. Liquid nitrogen oxide exhibits the same mechanical damage that can be felt as

Inadequacies such as liquid nitrogen, ingestion of the goods occur.

It is true that the regulations of the USA easily burst or jump, and patents 3,104,977 and 2,951,353 also for also the high freezing costs due to the high loading of particulate! Good taste for the recovery of the refrigerant. 50 could be applied, but this would be for Liquid carbon dioxide becomes considerable when it is directly exposed to damage cycle freezing process not applied to a large extent, changes in the structure of these arrangements, since it causes high costs and is not necessary, which only from the inventions according to the invention before Concerns about the treatment of nourishing tasks were developed. In carbonated agents. The fluorine-containing 55 the known arrangements is neither a good refrigerant are envisaged on a large scale as free-fall feed, nor will Coolant during processing and preservation in contrast to the arrangement according to the invention Used by food, however, the greatest possible turbulence is not sought, rather extensive use on a technical scale, there the turbulence of the coolant becomes so low kept for immersion freezing after direct contact 60 as possible.

method. It is known that the rapid freezing of According to a preferred embodiment of the

Moisture in fruits and vegetables batch process in which the frozen food before its

by direct immersion in liquid dichloro introducing into the freezing chamber by a stream

difluoromethane is carried out as a stage in the production of refrigerant vapor, is inventive

For frozen fruits or vegetable salad, the refrigerant is a fluorine-substituted alkane

to lead. There is also a device for rapid with 1 to 4 carbon atoms, which is a hydrate

objects or packages can freeze, and the refrigerant vapor removes this knows, in which the frozen food on an endless in the freezing chamber by interaction between

see moisture and refrigerant resulting hydrate of the refrigerant from the freezing chamber.

In a further embodiment of the method according to the invention, this is used in one closed by inlet and outlet valves from the outside air, at or below atmospheric pressure held freezer chamber.

The device for carrying out the method has a feed device for the continuous Feeding the frozen food in the form of individual particles to the freezer chamber and is marked through an inlet system with a feed chute for material feed by free fall into the Freezing chamber filled with liquid refrigerant, with a conveyor for continuous conveying floating particles of frozen food through the freezing chamber, which is closed by means of inlet and outlet valves away from the sink point, and an outlet system with discharge blades for discharging the frozen particles from the freezer compartment.

In a further embodiment of the device according to the invention, inlet and outlet valves Clamp valves used.

According to one embodiment of the device according to the invention, there is also an expansion valve for supplying liquid coolant to the freezing chamber at a point below the liquid level of the refrigerant and in the vicinity of the point at which the frozen goods are introduced into the liquid refrigerant intended.

The invention will then be described using an exemplary embodiment shown in the drawings described.

It shows

F i g. 1 shows an overall view of the device according to the invention for rapid freezing food,

F i g. FIG. 2 shows a modified embodiment of the device according to FIG. 1.

As a refrigerant for the inventive method are compounds or mixtures of suitable compounds whose normal boiling in the range of about -5 to - 50 are ⁰ C and its density is high enough in the liquid state at its boiling point, so that the food swim. The densities of the refrigerants at room temperature given below are lower than the densities under the freezing conditions. At temperatures above -5 ⁰ C, the food freezes only extremely slowly or not at all. At temperatures below -50 ° C undesired cracking or bursting of the food can take place. The recovery of refrigerants with boiling points below - 50 ° C may require the use of higher compression pressures and refrigerants other than water to condense, increasing freezing costs. The preferred freezing range is between -20 and -30 ° C. Therefore, refrigerants that boil in this range are preferred.

The density of the refrigerant at its boiling point at atmospheric pressure must be sufficient for the Frozen food floats in the refrigerant and easily rises to the surface of the liquid rise. The selection of refrigerants with such a density also means that foreign substances, which have a higher density than the refrigerant, e.g. B. small stones, pieces of metal and splinters of glass, separated from the food by sinking to the bottom of the freezer compartment.

Refrigerants that have boiling points and densities within the above limits are as follows Fluoro- and chlorofluoroalkanes:

boiling point density
at 25 ° C ⁰ C g / cm ³ Octafluorocyclobutane -6 1.48 Dichlorodifluoromethane .... -30 1.31 Monochloropentafluoroethane -39 1.29 Monochlorodifluoromethane -41 1.19

ao Also provide mixtures of these refrigerants and mixtures of the same with other compounds suitable refrigerants, provided their boiling points and densities are within the limits specified above lie. Certain mixtures give the possibility of extending the freezing range or medium freezing temperatures (and boiling points as well as densities) achieve that with the individual compounds cannot be achieved. An azeotropic mixture is particularly suitable; H. a mixture that delivers a distillate of the same composition and no change in its on evaporation Properties. However, an azeotropic mixture does not necessarily form, and its Education is also not essential as the evaporation that occurs in the freezing chamber does not causes disruptive changes in the properties of the refrigerant if the initial Composition of the mixture has been chosen correctly.

The refrigerant mixtures that can be used according to the invention include mixtures of dichlorodifluoromethane and monochlorodifluoromethane; the azeotropic mixture consists of 25 percent by weight of dichlorodifluoromethane and 75 percent by weight made of monochlorodifluoromethane and has a boiling point of -41 ° C and a density of 25 ° C of 1.22. Other mixtures that can be used are those of monochlorodifluoromethane and monochloropentafluoroethane. The azeotropic mixture of these compounds contains 49 percent by weight of monochlorodifluoromethane and 51 percent by weight Monochloropentafluoroethane and has a boiling point of -46 ° C and a density of 1.24. Mixtures from dichlorodifluoromethane and 1,1-difluoroethane (boiling point -25 ° C; density at 25 ° C = 0.89) can be used as refrigerants in the temperature range from -25 to -32 ° C at atmospheric pressure and have a density higher than 1 if the mixture contains 1,1-difluoroethane about 65 weight percent or less is limited. The preferred mixture of these two components is an azeotropic mixture with a boiling point of -32 ° C and a density at 25 ° C of 1.17 and has a 1,1-difluoroethane content of 26 percent by weight.

A suitable component for refrigerant mixtures with medium freezing temperatures is 1,2-dichlorotetrafluoroethane with a boiling point of 3.8 ° C

and a density of 1.43. Ranges of freezing temperatures made with the help of mixtures 1,2-dichlorotetrafluoroethane and other refrigerants can be achieved, as well as the corresponding ranges of compositions are in the following Table specified:

Refrigerant mixtures with 1,2-dichlorotetrafluoroethane

Freezer area Maximum Content of Second component 1,2-dichlorotetra
fluoroethane -5 to -30 ° C Weight percent Dichlorodifluorine methane -5 to -39 ° C 88 Monochloropenta- fluoroethane -5 to -41 ° C 90 Monochlorodifluorine methane 95

Although the natural moisture in the food and any water residue from previous Treatments such as bleaching, washing and the like quickly freeze when the food come into contact with the liquid refrigerant, the food must be in a turbulent state Conditions are maintained until the water is sufficiently frozen to cause the agglomeration to agglomerate Prevent food.

The turbulence that is required to move the food particles Keeping them separate from one another at the beginning of the freezing process can sometimes do through the turbulence-generating effect of the liquid refrigerant can be brought about when the recovered Refrigerant vapor in the form of a pressurized liquid in the circuit Freezing chamber is returned. The circulation of the refrigerant near the point where the food falling into the freezer compartment causes constant violent agitation Splashing, whereby the food particles being fed are kept separate from one another. Further turbulence occurs on the surface of the refrigerant if the relative warm food comes into contact with the low-boiling refrigerant and quickly Lead to evaporation of the same. When the food is carried away from this area of turbulence the ice coating prevents them from agglomerating during the further freezing process, if the food is stacked lower to complete the freezing process.

The required turbulence can also be achieved by circulating the liquid refrigerant are brought, with an ebb and flow of liquid on the surface of the fall area the food is created. A mechanical stirrer can be provided to stir the refrigerant Keep moving enough to keep the particles separate from each other for the initial freeze-out to keep.

Dichlorodifluoromethane which can be used in the process of the invention Form a crystalline or semi-solid hydrate in the presence of water vapor, which at freezing temperature is stable, but easily into the refrigerant at temperatures above the freezing point of the water and water disintegrates. Moist air that goes with the food in the freezer penetrates and leads to the formation of this hydrate with the refrigerant, can be mist or snow-like Particles to be visible. When the hydrate particles are

ίο deposit on the surface of the food, give it to food when it is warmed to room temperature as a result of decomposition of the hydrate and the evaporation of the refrigerant component from the hydrate an harmless, frothy appearance. The hydrate formation should therefore be prevented, or at least at least, as far as possible by reducing the direct contact between the outside air and the refrigerant vapors in the freezer compartment is prevented. If hydrate does form anyway, it will be constant through the flowing stream of refrigerant vapors, e.g. B. to the suction side of a compressor, from the food washed away and discharged from the freezer compartment. In order to be as quick and as complete as possible To achieve removal of any hydrate that forms, there is a vent line for the refrigerant vapors to the compressor, preferably near the feed chute for the food, where moist air can inadvertently enter. This causes the contamination to be frozen Foods with the hydrate that may be formed are practically avoided.

When the hydrate particles are flushed out of the freezer compartment by the refrigerant vapors, they decompose due to the heat of compression in the compressor. From this point on, the refrigerant will Maintained above the decomposition temperature of the hydrate until it passes through the expansion valve again is returned to the freezing chamber. The water of hydration is from the refrigerant in the separator described below. In the following exemplary embodiments uses water-cooled, two-stage, non-lubricated reciprocating compressors; however, you can also do others Use types of compressors. If appropriate oil separators are provided, one can also work with lubricated piston compressors. Centrifugal compressors are also suitable for large systems.

The difficulties arise due to the condensation of the refrigerant at temperatures above 0 ° C the formation of ice or hydrate coatings on the heat exchange surfaces is avoided. In view of the easy availability of freezer systems designed for operation at -40 ° C, the condensation can also be carried out at this temperature, if the system accordingly is built. Multiple condensers can be provided for intermittent periods of operation Facilities to remove the ice on mechanical wepe or by heating. Washers, centrifuges or other gas cleaning equipment can be used to remove ice and hydrate particles the way to remove the condensers.

The freezer chamber can habp ^ cylindrical shape and be equipped with a screw conveyor. With such a shape, the required small Distance between the outer edges of the win-

fertilize the screw conveyor and the wall of the freezing chamber at the cutting line of the surface of the refrigerant and the freezing chamber wall are paused. If this distance is at the The surface of the refrigerant is small, the food is conveyed through the freezing chamber; without being crushed between the edges of the turns of the screw conveyor and the freezing chamber wall to become and without moving backwards. A clearance at the bottom of the freezer compartment allows the refrigerant to flow back from the outlet to the inlet end of the freezing chamber below Circulation through the second condenser. This also prevents foreign matter from sinking in the sump of the chamber allows. When a distance of the order of 0.16 to 0.32 cm between the turns of the screw conveyor and the chamber wall on the surface of the refrigerant is paused, the distance at the bottom of the chamber can be within wide limits of 0.16 to 5 cm or more and the shape of the bottom of the freezing chamber is immaterial.

The number and distance of the turns of the screw conveyor can be changed from one another vary, provided only the food particles have enough space to freely grow on the surface of the Of refrigerant to float between the coils near the feed end. The turns can have different distances from one another, as shown below with reference to FIG. 2 is described so that the food that gets into the space where the turns of the screw conveyor have smaller distances from one another than the turn or turns at the inlet end the screw conveyor, are pushed together and form several layers. At this time the surfaces of the particles are covered with an ice glaze and the particles do not adhere to each other and don't freeze together. The over the surface of the refrigerant in the form of several Food placed in layers can be frozen completely, e.g. B. by spraying with the coolant from above or by arranging stirring bars at different points between the turns of the screw conveyor. The screw conveyor can be built so that it can with rotates at different speeds, d. that is, it can have turns with equal spacings from one another and a two-section shaft so that one end of the auger can turn faster than the other. Usually the inlet end of the screw conveyor is running faster than the section at the outlet end. Under these circumstances, the foods pile up between the slower rotating turns in several layers, which are sprayed with refrigerant or stirred to freeze completely.

To further explain the invention, reference is made to FIG. 1, in which a particular embodiment a device for the continuous freezing of 23 kg of food per hour in Contact with a boiling refrigerant is shown schematically.

The individual food particles 10 are fed into the hopper 11, from where they pass through pass the channel 13 in a second hopper 14 when the vibrating device 15 by a Signal from the sequence switch 17 is actuated. Then the frozen food is synchronized by a sequence of Valves in intake system I directed to freezing chamber 29. The inlet valves are sequentially operated to reduce the loss of refrigerant vapors and the ingress of air and moisture as far as possible and avoid damaging the food 10. There will always be only one of the valves 18 and 19 open, so that the

ίο feeding from the feed hopper 14 through the open valve 18 into the chamber 20 and, when the valve 18 is closed, out of the chamber 20 falls through the open valve 19 into the feed chute 21. The pneumatic vibrators 22 and 23 ensure that all of the food load falls cleanly through the open valves. A vibrating device 24 with adjustable speed on the feed chute ensures that the supplied food particles separately from each other in the boiling refrigerant 28 in the Freezer compartment 29 fall. The freezing of food or entrained water at the end of the day Slide 21 is prevented by the electric heater 30. The freezing chamber consists of one 25 cm wide and 76 cm long transparent cylinder made of polyacrylic resin.

The effective heat transfer from the frozen food 10 is ensured by the fact that the refrigerant is in motion as a result of its boiling, the frozen food particles fall down individually and the recovered refrigerant is returned through the nozzle 31 located in the area where the frozen food falls will. The frozen food particles immediately freeze on the surface and are coated in this way a glaze so that they do not agglomerate when they get into the area of the screw conveyor 32 to swim. The screw conveyor has a diameter of 25 cm and five turns with spacing each 12.7 cm. The speed of rotation of the screw conveyor and the dwell time of the frozen food in the freezing chamber are controlled by the drive 33 with speed control.

When the frozen food is conveyed through the freezing chamber, it floats as a single layer on the refrigerant, or it collects in several layers over the surface of the refrigerant on. In order to ensure that these layers are completely frozen, the frozen food can be removed from the Spray nozzles 35 are sprayed with refrigerant which is circulated by the pump 34.

The frozen goods are conveyed through the freezing chamber to the area of the discharge blades 36. Preferably two such blades are provided, which are perforated so that the refrigerant can flow out that are curved to make it easier to pick up and hold the refrigerated goods, and which are arranged at an angle to the frozen food over the barrier wall 37 in the discharge channel 38 to be carried out. Then the frozen food is synchronized by a second unit Valves discharged from the freezing chamber into the exhaust system 0. This process plays out as follows: The sequence switch 39 opens one of the clamping valves 40 and 41, so that a certain amount of the frozen food falls from the outlet channel 38 into the chamber 42, from where it falls further into the container 43. This valve system serves as well as that on the inlet side of the

009 545/203

9 10

Freezer to reduce the loss of similar particles from the gaseous refrigerant refrigerant vapors, taken to the exclusion of air and electricity to the compressor. This damp-dampness out of the system and to avoid activity collects as an upper layer of liquid in the damage to the food, although the first gas-liquid separator 61 is on. she will Food in the frozen state not abso 5 as required through a valve of a known type easily damaged as drawn in unfrozen.

Conditions. In the closed chamber 42, all of the water carried by the recovered food particles under the action of a liquid refrigerant will be frozen when the vacuum created by the vacuum pump 45 is exposed to approximately 68.6 cm of mercury through the expansion valve 63 to reduce the io flows, and covers the passages of the expansion amount of refrigerant, which is still on the opening valve, whereby the flow of refrigerant is to reduce refrigerant and low, but is hindered. This water freezes because significant quantities of the refrigerant regain the pressure on the liquid refrigerant. B. 14 atü, have been discharged on the atmosphere chamber. The pneumatic 15 pressure is relaxed and the temperature of the Flüs-Rüttelvorrichtung 46 ensures the complete sigkeit thereby suddenly drops. The coating emptying of the chamber 42 through the lower outlet of the valve surfaces with ice occurs even when the valve 41 enters the outlet channel 47. This channel is designed as an angle stop valve with smooth flow through the nozzle 48 with dry air to channels and so close as possible to exclude the moist outside air, the ice formation 20 wall of the freezing chamber is arranged. Since the accumulation of ice in the valve on the outlet valve and on the surfaces of the discharge channel and restricts the freezing of the refrigerant, the liquid level rises to the valve or to the channel to be in the first separator 61 Avoid this fluid level. In order to prevent the upper valve from being closed by the pneumatic liquid level regulator 40 when frozen food is still being measured through it, which is running under the same with a compressed air supply, the cam switch 50 is at a pressure of 1.4 kg / cm ^{2 is} connected. When the movement of the discharge blades is synchronized. the liquid level rises, so does the air

The gaseous refrigerant in the freezer chamber is pressurized to the expansion valve. This opens

the valve widens through the outlet 52 near the inlet and allows a reinforced

end of the freezing chamber to the recovery flow of the liquid refrigerant. If the

system fed. The recovery system for valve opening is narrowed by ice, the increases

the refrigerant consists of the water-cooled, liquid level.

two-stage, unlubricated compressor 53 with an If the full available control pressure is not in the capacity of 0.2 effective m ³ / min. and the working status is to open the valve, the pressure is set with a delivery pressure of 14 atü. This compression switch 72 fixes this pressure and actuates the compressed gaseous refrigerant in repetition timer 73. The timer in turn actuates the water-cooled first condenser 60, from which a three-way solenoid valve is actuated, which supplies a liquid mixture of water and refrigerant Relief valve exerted pressure rapidly pul the first gas-liquid separator 61 flows. That lets sieren, so that the valve is alternately opened separated liquid refrigerant is through the 4 ° and is closed until the ice is released and the liquid level regulator 62 over the expansion liquid level in the separator back to valve 53 in the nozzle 31 in the freezing chamber - the normal height has decreased. Now the pressure returns. The non-condensed gas from the switch the repetition timer and the Maersten separator 61 flows through the second congestion valve inoperative until the next iron capacitor 64, which occurs in the bottom of the freezing chamber 45 collection. In this automatic way there is located and is cooled by refrigerant, which keeps the expansion valve free of ice without interrupting the work of the freezer caused by the pumping action of the screw conveyor. Such a wallowing is. The condensate from this condenser control of the expansion valve is essential for the trouble-free operation of the device in a second gas-liquid separator 65,
collected and fed back by the liquid level regulator 5 ° Instead of the pneumatic liquid level 66 via the valve 67 in the circuit in the freeze regulator 62, an electronic liquid level chamber can be fed back. The non-condensed gas regulator, a combination of. A pneumatic from this separator is discharged to the outside air via the non-return liquid level regulator or a combination of valve 68. A part of the gas flow from an electronic liquid level transmitter from the first separator 61 is used via 55 and an electronic liquid level regulator, the control valve 69 for the inlet of the compressor. Each of these regulators can be fed back, depending on how it is equipped to maintain an automatic reset, establishing a pressure in the cooling chamber from 0 to , the liquid refrigerant spherical pressure is required to avoid losses of 6p charge in the device via the return gas refrigerant. recovery system supplied to the storage container 74

Water that will be in the with the frozen food. The reservoir 75 is a normal one

Freezer enters, freezes to small pieces of ice, shipping container for the refrigerant,

which float on the refrigerant and without an electrically heated evaporator 76 is used for

Difficulties together with the frozen food part 65 the need to separate the refrigerant from

can be deducted. Moisture in the accumulated food oils or other

Vapor phase over the falling area of the frozen food impurities. Liquid refrigerant flows through

condenses and freezes, is in the form of snow-gravity from the bottom of the freezing chamber to the

11 12

Evaporator. The withdrawing refrigerant vapors 4 and 35 ° C, can condense. Such a con becoming led to the inlet of the compressor, while the densation temperature is chosen to be the light the residue in the evaporator through the valve transition and finally the removal of the water 77 can be deducted. The valves 78 and 79 are used as a liquid to facilitate.

tie the evaporator to the freezer 5 A schematic representation of a device

or turn it off. . for continuous freezing of food

All metal parts of the freezer that are being blown at a speed of approximately 136 kg / hour. is

Coming into contact with food consist in FIG. 2 shown.

made of stainless steel. The heated and cooled freezer compartment of this 136 kg / hour. Process surfaces are equipped with thermal insulation, io the system is a container made of stainless steel with to save energy and protect the operators to a semi-cylindrical round bottom of 25 cm. Rods 80 (one of which is shown in Fig. 1 radius and with straight sides above the bottom) are used to detach ice and cut off 31 cm high and a food particle by hand, if this requires plastic windows on the front, around which funding should be required. 15 snail to be able to visit. The inside length is 183 cm. The feed speed of the food is 183 cm. This freezing chamber is equipped with a means of the freezing chamber can be varied, screw conveyor, the first turn of which is changed by changing the time during which the gel has a width of 38.1 cm and in a product to be frozen in the chamber 20 between the inlets - Stand 17.8 cm from the inlet end of the chamber and by keeping the shaking motion 20 in order while the next nine turns of the shaking device 24 are regulated. The dwell times have a distance of 12.7 cm from one another and in each case r in the freezing chamber will have a radius of 24.9 cm from the revolution. The conveyor speed of the screw conveyor is determined. The changing screw is positioned in such a way that it stands from the bottom of the stanchions at the discharge speed of the goods that are frozen in the middle of the same at a distance by changes in the 25 by 0.8 cm. The time that the screw turns are controlled, for which the material remains in the outgoing shaft at the outlet end with four perforated vacuum chambers. In this way, the blades can be equipped for discharging the frozen goods from the supply, dwell time and discharge time for each of the freezing baths. These blades can be synchronized in such a way that a piece of stainless steel, which in a flat state is completely frozen product using a square 25 cm on a side, using the least possible amount of refrigerant in one direction with a radius of 15 To get 2 cm. The freezing chamber can be curved under positive pressure, a ladle, rounded on one side at atmospheric pressure or at reduced pressure so that it can be operated by the wall of the freezer. Chamber stand at a distance and at an angle The types of inlet and outlet valves can be 35 arranged. Further, the freezing chamber is also subject to modification and is not limited to the pinch valves mentioned in the description of a sump 81 for collecting heavy foreign matter and the following items associated with frozen food. Which are introduced and from time to time determined by the size of the valve according to the amount of valve 82 to be withdrawn. The sieves 83 in the bottom of goods that must be conveyed through the valve in the freezing chamber at the openings to the second in the unit of time, in order to let the freezer with condenser work at full capacity. Since the task of preventing entry into the condenser,
The valve systems for supplying the frozen food and the amount of air and moisture to the freezing chamber and the removal of the same moisture that gets into the system must also be given an I in this case or 0, any valve can be used which are the same as those shown in FIG. 1.
fulfills these tasks and easily and continuously The refrigerant vapor compressor has a capacity working without the food, especially at that of 2.1 effective m ³ / min. Damaging the device according to the feed side of the device. Fig. 2 is equipped with an outer endless conveyor belt. For example, torsion valves can be used to divert the prepared for freezing. Torsion valves are to be fed to inlet system I in the food in the open state. The essential flexible rubber hose connections. Sequence switch for the actuation of the inlet valves. By turning one end or both, you will simultaneously control the drive motor 16 for the ends of the hoses at the connection points. 55 funnel to prevent. The feed chute from the evaporation rate of the refrigerant inlet valve to the freezing chamber has an outlet 25 in the freezing chamber varies with the supply for excess water, which is driven by the sieve 26 and the initial temperature of the covered and equipped with the water lock 27, frozen goods and with the heat of vaporization of the refrigerant to prevent air from entering at this point. The amount of as such or in the form of 60 dem. The endless belt 44 conveys the frozen refrigerant evaporating from the hydrate varies foodstuffs away from the outlet valve 0. From about 136 to 318 kg for every 45 kg of food. cold, dry, non-condensed gases from the The compressor must be able to get this amount to the second gas-liquid separator to enforce in the refrigerant vapors. The compressor outlet channel of the outlet system through the nozzle 49 wii-d expediently operated at a pressure in the region of 65 and help to keep the air humidity away from 14.1 atmospheres so that it can maintain a mixture.

Refrigerant and water above freezing point As shown in FIG. 1 described, the

of the water, e.g. B. at a temperature between about frozen food of the action of a

13 14

Exposed to vacuum to freeze the remaining refrigerant since the plate freezing process,

to remove from. Air, which is normally the va-

vacuum chamber fills when the food is made available from the frozen individual particles,

can carry large amounts of moisture. Frozen food that is under the drainage

keep. To prevent the accumulation of ice from this dampening or mechanical damage in fan

The air in the discharge vacuum chamber to air freezers can now suffer

hesitate, the chamber is left unchanged by the vacuum pump according to the present invention

51 (Fig. 2) partially evacuated when the valves freeze.

are closed and the pump for extracting the example of vegetables, which are according to the

Refrigerant is not in operation. · Freeze the invention in a cheaper way

The auxiliary compressor 54 is operated when the celery, eggplant, green peppers, radishes, tomatoes

Freezer following periods, in th and mushrooms. Grapefruit and orange slices as well

where no foods have been frozen, peaches are examples of fruits that still exist today

kept in readiness for immediate use not frozen to any significant extent,

shall be. The valves 55 to 58 serve this purpose, but according to the invention more satisfactorily

neither the main compressor nor the auxiliary compressor can be frozen. Fruits like

put into operation. The buffer chamber 59 steams apples, sugar melons, peaches, pineapples, cherries

the pressure fluctuations in the return line for and strawberries, which are sometimes contained in sugar syrup.

the refrigerant vapors and prevents frozen or frozen blocks from entering the store

are brought into the suction lines of 20 by liquid refrigerant, can be with the help of the invention

Refrigerant compressor. . according to the boiling refrigerant used easily in

The arrangement around the expansion valve unsatisfactorily in the form of individual, free Freeze interrupted operation and free from ice clogging and flowing particles. Grapes and in gen is the same as sliced avocados, which are usually called Fig. 1. The gas-liquid separator for the pulp to be frozen can also be used in the 136 kg / hour processing device is freezing with a device according to the invention. In all Second liquid level regulator 70 equipped, the cases will be large fruits and vegetables the accumulated water level in the separator is displayed, preferably in slices, cubes or spheres and a warning signal for the cutting to be removed. Blueberries and raspberries can be used Water through the valve 71 is. 3 ° according to the rapid freezing process according to the invention

Rapid freezing of foods individually for noticeably better frozen produce

the invention enables the economic income to freeze. The slow freezing of

storing food in bulk, packing blueberries leads to e.g. B. when defrosting to a

same for distribution in any desired tough and rubbery structure. Just before

The berries are classified by quantity and availability of food 35 from freezing

freed for use by the consumer without stalks, washed and stored in a

lust and delay. Brought suitable condition through the measure of indirect consumption.

Introducing the food into the freezer compartment The larger fruits, apples, apricots, peaches,

in the form of individual, separated partial plums and the like, are peeled, pitted and in

A free-flowing frozen sample is obtained in a form suitable for immediate consumption

in contrast to the previously common blocks of halves, quarters or smaller pieces.

of frozen fruits and vegetables. brings.

In the method according to the invention, the vegetable plants, such as peas, beans (Lima or

Freezing food unit first (shell bonnen), fire beans, small or in cubes

encapsulates. This encapsulation creates the immediate 45 cut beets, diced carrots

bare contact of the food unit with the and pieces of asparagus, are well suited for insertion into

liquid refrigerant is essentially avoided, which the freezing chamber and for the preparation of free

Food unit is physically protected flowing, satisfactory frozen product

and the natural state of the food unit.

remains. . 50 fried potatoes and meat, such as beef, pork,

According to the method according to the invention, veal and lamb, as well as poultry and seafood of the most varied kinds, can advantageously be frozen, such as mussels, shrimp, fish fingers and the like. This freezing process often leads to a more pleasing appearance and texture of the manner in accordance with the invention. Normally, the food is frozen as if the food with large pieces of meat or fish are frozen into smaller pieces using the previously known technical equipment, of suitable size and shape, such as cubes. The more pleasing appearance makes cuts that are noticeable for use in stews, especially with foods that are suitable for dishes, soups, and the like, and these pieces can break the cell walls with suitable materials, such as breadcrumbs, when freezing according to the hitherto customary technical methods the formation of large flour, corn flour and the like., are coated.
Ice crystals shatter during the relatively slow freezing process to date. Foods that are

not yet freeze satisfactorily Example 1
can often be reduced as a result of the rapid

freezing effect of the boiling refrigerant after the 65th

Method according to the invention in a satisfactory manner. In the device according to FIG. 1 be lima way freeze and freeze. Food frozen beans. The inlet and outlet valves hitherto usually in tightly packed blocks after are clamping valves with a clearance in front

6.4 cm and with rubber linings. As a refrigerant dichlorodifluoromethane is used and the beans stay in the freezer for 2 minutes.

113 kg of lima beans are frozen in the course of 5 hours. The loss of dichlorodifluoromethane is 4 kg per 100 kg of frozen beans. The recovery of the refrigerant is at least 99.0%. The frozen product contains less than 0.02 percent by weight dichlorodifluoromethane and has a pleasing appearance in terms of color and texture. After thawing and cooking the vegetables are judged to be of consistently fine quality.

In the same freezer, with the help of dichlorodifluoromethane, slices and Diced carrots and potatoes, fried potatoes, one made from lima beans, corn and carrots mixed vegetables, prawns, clams, fish fingers, plums, grapes and strawberries frozen. In all cases, the freezing process is quick, and the result is a frozen one that is pleasing to the eye Product, and the product is highly suitable for consumption after thawing.

The dichlorodifluoromethane is replaced by octafluorocyclobutane and peas are frozen in the device loaded with this refrigerant. In view of the higher freezing temperature of octafluorocyclobutane (C -6 ⁰⁾ the residence time of 2 minutes for the with dichlorodifluoromethane at will - 30 ° C the frozen lima beans to 4 minutes longer. A frozen product of good appearance and fine quality is obtained.

35

Example 2

The on the basis of Fig. The method explained in FIG. 1 is carried out in the device according to FIG. 2 carried out. the Inlet valves are clamping valves with a clearance of 12.7 cm, while as exhaust valves Clamp valves with a clear width of 15.2 cm can be used. Using dichlorodifluoromethane strawberries are used as a refrigerant at a rate of 147 kg / hour. quick frozen. Both the frozen product and the thawed product are color, Appealing taste and texture. In a similar way, cut beans, 5 cm pieces of cauliflower, 5 to 10 cm long asparagus pieces, Brussels sprouts and peas are frozen in the device, whereby the refrigerant requirement 0.9 kg for every 45 kg of food and the degree of recovery of the refrigerant is at least 99%. The various frozen products contain less than 0.02 percent by weight refrigerant.

Freezing speed refers to the time it takes to eat a specific unit of food to freeze. For example, a unit of 136 kg of food refers to one Approximate freezing time of 15 minutes. If it takes less than 15 minutes, it will increase Capacity of the system, e.g. B. due to the capacity of the compressor. If more than 15 minutes to the Freezing of a given unit amount is required, the rate of freezing will decrease.

Claims (10)

Patent claims: 1. Method for quick freezing food in a freezing chamber containing a Contains liquid refrigerant that is in direct contact with the in the form of individual loose particles present food stands, characterized in that the frozen food in free fall is fed to the refrigerant and moved further floating therein and that Refrigerant is in a turbulent state at the point of free fall. 2. The method of claim 1, wherein the frozen food prior to its introduction into the freezing chamber is passed through a stream of refrigerant vapor, characterized in that the refrigerant is a fluorine-substituted alkane with 1 to 4 carbon atoms, which can form a hydrate, and the refrigerant vapor that created in the freezing chamber by interaction between moisture and refrigerant Hydrate the refrigerant removed from the freezing chamber. 3. The method according to claim 1 and 2, characterized in that it is using in one Freezing chamber closed off from the outside air by inlet and outlet valves, kept at or below atmospheric pressure is carried out. 4. The method according to claim 3, characterized in that the remaining refrigerant Frozen food after it has been discharged from the freezer chamber and before it comes into contact with the outside air withdrawn, recovered and returned to the freezing chamber in a liquid state will. 5. The method according to claim 4, characterized in that the liquid in the freezing chamber is returned to the circuit through a pressure relief valve located under the Surface of the liquid refrigerant is located near the point where the frozen food enters the refrigerant falls. 6. The method according to claim 4, characterized in that the frozen food after removal the remaining refrigerant and before contact with the outside air with dry air is rinsed. 7. Device for performing the method according to claim 1 to 6 with a feed device for the continuous supply of frozen food in the form of individual particles to the freezing chamber, characterized by an inlet system (I) with a feed chute (21) for feeding the material by free fall into the freezing chamber (29) filled with liquid refrigerant (28), with a conveyor (32) for continuously conveying floating particles of frozen food through the freezing chamber closed by means of inlet and outlet valves (18, 19, 40, 41) from the sink point fort and an outlet system (0) with discharge blades (36) for discharging the frozen Particles from the freezer compartment. 8. Apparatus according to claim 7, characterized in that as inlet and outlet valves (18, 19, 40, 41) pinch valves can be used. 9. Apparatus according to claim 7, characterized by a relief valve (63) for the supply liquid coolant in the freezing chamber 009 545/203 a point below the liquid level of the refrigerant (28) and in the vicinity of the introduction point of the frozen goods in the liquid refrigerant. 10. The device according to claim 7, marked characterized by a vacuum pump (45) for drawing off residual refrigerant under subatmospheric pressure from the frozen goods in a Chamber (42) and through a nozzle (48) for dry air in the outlet channel (47). 1 sheet of drawings